Electrical sliding contact.



J. V. PURSSELL.

ELECTRICAL SLIDING CONTACT.

APPLICATION FILED DEO.12, 1912.

Patented Dec. 2, 1913.

WITNESSES INVENTOR COLUMBIA PLANOGRAPH cc.. WASHINGTON. u. c.

A llornzy UNITED STATES PATENT OFFIQE.

JOHN V. PURSSELL, OF FRIENDSHIP HEIGHTS, MARYLAND.

ELECTRICAL SLIDING CONTACT.

To all whom it may concern Be it known that I, JOHN V. PURSSELL, a citizen of the United States, residing at Friendship Heights, in the town of Bethesda, county of Montgomery, and State of Maryland, have invented certain new and useful Improvements in Electrical Sliding Contacts, of which the following is a specification.

IVhile I shall, for the purpose of illustrating my invention, describe it in con nection with a tuning coil of wireless telegraphy it will of course be understood that it may be used in telephony and other branches of the electrical arts, where an efficient and easily operated sliding contact is needed. Sliding contacts, broadly considered, are, of course, old.

One of the principal objections to sliding contacts, now in use iii-wireless telegraphy is the rapid wearing down of the wire of tuning coils, etc., on which they are used, and the reduced efliciency of such coils resulting from the lodgment of metallic particles between the turns of the wire where they cause a partial short circuit.

The object of my invention is to eliminate the wearing down of the wire turns, the deposit of metallic particles between the coils and the resultant partial short circuit.

A still further object of my invention is to maintain a maximum efliciency in the tuning coil; and with these and other objects in view my invention consists of the parts and combination of parts as will be hereinafter more fully pointed out.

In the drawings: Figure 1 is a top plan view of a tuning coil with my invention in place. Fig. 2 is a sectional view on the line 22, Fig. 1. Fig. 3 is a perspective view of my improved slide contact. Fig. 4c is a transverse sectional view of the slide contact. Fig. 5 is a top plan view of my improved sliding contact.

The reference numeral 1 designates a tuning coil, such as is used in wireless telegraphy on each side of which is the usual slider rod 2, all of which may be of any approved construction.

Specification of Letters Patent.

Application filed December 12, 1912.

Patented Dec. 2,1913.

Serial No. 736,341.

My improved sliding contact comprises a piece of rebent spring metal 3 which is rebent at one end to form a loop 4, the arms 5 and 6 of which are of such length that the insulated finger piece 7, T shaped in cross section, may be secured between said loops and leave a space between it and the loop to receive the slider rod 2. An insulated finger piece 8 is secured to the free end of the sliding contact. A contact 10, preferably blunt or rounded, as shown, is secured to the sliding contact spring. This contact 10 may be riveted to the spring or it may be struck up from the spring as found most desirable. Theformation of the spring body 3 is such that, when the slider is in position on the slider rod, the contact 10 is normally pressed against the tuning coil 1. henever it is necessary or desirable, to move the contact point 10, from one turn to another on the coil, it may be lifted from the wire by grasping the insulations 7 and 8 between the thumb and forefinger, whereupon the sliding contact may be moved along the slider rod 2 without any danger of abrasion of the wire, thereby eliminating all danger of partial short circuits between the turns of wire.

One of the valuable features of my invention is its simplicity and certainty of action, the single piece of spring metal 3 interposed between the slider rod 2 and the coil 1; or other device upon which it is used, insuring a firm and efiective contact, such as cannot always be obtained with sliders of the ball and spring type. Smoothness of operation is another advantage secured by my improved slider, which results in reducing to a minimum all noise incident to shifting the slider, whereby I have been enabled, in actual practice, to distinctly hear the faintest signals in wireless telegraphy while tuning.

IVhat I claim is:

1. A slider contact comprising a single piece of metal having a substantially U shaped bend at one end and a right angle bend at the other end, a contact carried by said metal intermediate its ends, a T shaped insulated finger piece secured in said U ing rebent at one end to form a slideway for shaped bend and an insulated finger piece a slider rod. 10 secured to said right angle bend. In testimony whereof I have ZLlfiXGCl my 2. A slider contact comprising a rebent signature in presence of two Witnesses.

spring body With its ends normally spaced JOHN V. PURSSELL. apart, a contact carried by said body intermediate its ends, insulated finger pieces secured to the ends of said body, said body belVitnesses:

HENRY W'. OFFUTT, G. FRANCIS BROWN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

